Apparatus for carrying out reactions with wire gauze catalysts



May 2, 1939.

o. BAADER APPARATUS FOR CARRYING OUT REACTIONS WITH WIRE GAUZE CATALYSTSFiled Sept 8, 1957" 3 Sheets-Sheet l Otto Baad/er INVENTOR.

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May 2, 1939. v o. BA'ADER I 2,1 APPARATUS FOR CARRYING OUT REACTIONSWITHWIRE GAUZE CATALYSTS Filed Sept; 8, 1957' I 3'Shets-Sheet gINVENTOR.

Otto Badder Hi6 ATrLORN Ys Ma 2, 1939. 0. BAADER 2,156,422

APPARATUS FOR CARRYING OUT REACTIONS WITH WIRE GAUZE CATALYSTS FiledSept. 8, 1937 3 Sheets-Sheet 3 INVENTOR. Otto .Baader BY MAW- H ISATTORNEY 8 Patented May 2, 1939 APPARATUS FOR CARRYING OUT BEAC- TIONSWITH WIRE GAUZE CATALYSTS Otto Baader, Ludwigshafen-on-the-Rhine,Germany, assignor to I. G. Farbenindustrie Aktiengesellschaft,Frankfort-on-the-Main, Germany. Application 3 Claims.

The present invention relates to improvements in apparatus for carryingout reactions with wire gauze of catalytically active metals.

The wire gauze constructed of catalytically active metals, such asplatinum or its alloys, which are arranged transverse to the directionof flow of the reactants in catalytic reactions, in particular in theoxidation of ammonia, are subjected to quite considerable strain by theworking temperatures which are frequently very high. The wire gauzeexpand when heated and tend to bulge by reason of their own weightand/or the pressure of the reactants flowing therethrough. This strainon the wire gauze leads to a shortening of its working life. It hastherefore already been proposed to subject the wire gauze to a strongtensile stress by loading with weights or by spring action. It is notadvisable, however, to expose the sensitive wire gauze to such strongtension, especially since the latter is increased by the pressure of theflowing reactants. According to another proposal, the wire gauze isprovided with supports, especially supports of heat-resistant metals.However, such devices fulfil the desired purpose for long onlyincompletely, in particular because they themselves are subjected to theexpansion phenomena caused by the heat.

I have now found that bulges in the wire gauze can be effectivelyprevented even in continuous operation by taking care that the supports,advantageously used in the form of wires, are kept in a tightlystretched state during the operation by a device which actsautomatically. In this way mechanical strain on the wire gauze isappreciably reduced; this not only results in a considerable increase inits working life but also renders it possible to pass through aconsiderably larger amount of reaction gases per unit of surface of theca'talyst net than without the said device.

The supporting wires may be arranged parallel to each other or at anangle to each other and on one or both sides of the wire gauze which isarranged in the reaction chamber in a horizontal, vertical or inclinedposition.

Devices for constantly keeping wires under tension are already known,for example in apparatus for electrical gas purification, but theemployment of such devices in combination with wire net catalysts isnew.

The invention will now be further described with reference to theaccompanying drawings which show arrangements of apparatus according tothis invention but the invention is not September 8, 1937, Serial No.162,953 11 Germany January 30, 1936 restricted to the particulararrangements shown.

Figure 1 is a vertical section through a. reaction chamber.

Figure 1a is a plan view of the mid-section of the chamber shown inFigure 1.

Figure 1b is a detailed view illustrating a. manner in which thesupporting wire may be fastened to the walls of the apparatus.

Figures 10, 1d and 1e are detailed views showing various modificationsof applicants invention.

Figure 2 illustrates another means for keeping the supporting wire taut.

Figure 2a is a plan view similar to that of Figure 1a in which the meansof keeping the supporting wire taut is that shown in Figure 2.

Figures 3 and 3a correspond to Figures 2 and 2a respectively andillustrate a further modification of applicant's invention.

With reference to Figure 1, R denotes a reaction chamber provided withflange rings B and B, supporting wire A, and catalytic screen J.Catalytic screen J is not attached rigidly to any portion of theapparatus and is, therefore, free to expand and contract without beingsubjected to tensile stress or bending. Since the supporting wire A ispositioned above screen J, in this instance it is obvious that thereaction chamber shown in Figure 1 is one through which the reactiongases pass in an upward direction.

A plurality of supporting wires A may be and preferably are employedthroughout the crosssection of the apparatus. Said supporting wires A,which pass through the reaction chamber, may be fastened to the wallsthereof in the following manner. At one end the wires are thickened andthe thickened portions thereof are positioned in cavities in theflangering in order to provide a firm hold at said end. At the other endeach wire A projects beyond the chamber wall and is not fixed. It iskept under tension by means of compression spring 3 acting upon nut 4threaded upon the end of supporting wire A. Stufiing box I serves toprevent any of the reaction gases from leaking out of the chamber bypassing along supporting wire A, and collar bearing 2, which is notrigidly attached to supporting wire A,'serves the double purpose ofkeeping packing box I in its proper position and as an abutment forcompression spring 3. Nut 4 is tightened so as to give supporting wire Athe proper amount of tension when the apparatus is cold. As saidapparatus becomes heated, wire A will tend to expand and is allowed todo so by means of the described device without any decrease in itstension. Thus it may be seen that the supporting wires A require nofurther adjustment even though they are rapidly heated and cooled.Instead of the tension device being arranged at only one end of eachwire A, it may also be arranged at both ends of each supporting wire.The number of supporting wires A used depends upon special requirementssuch as the active area and thickness of the metal wire screen J.

The relative position of supporting wires A, with respect to metal wirescreen or screens J, may be varied in several ways, depending upon thedirection of the flow of the reacting gases. Thus Figure 10 illustrates,as does Figure 1, a modification wherein supporting wires A arepositioned above catalytic screen J so that the latter may begivensupport when reacting gases are passed through chamber R in an upwarddirection. It is evident that supporting wires A may also be positionedbelow catalytic screen J, as illustrated in Figure 1d, so that thelatter will receive support from the former when reacting gases arepassed through chamber R in a downward direction. A furthermodiflcation, il lustrated in Figure 1e, is that of positioningsupporting wires both above and below catalytic screen J. This lattermodification is particularly suitable when the reacting gases are passedthrough chamber R in alternating directions. It is obvious, of course,if two or more catalytic screens are required, that supporting wires Amay be positioned between and on either or both sides of said catalyticscreens.

In the arrangement shown in Figure 2, a helical spring 6 acts uponscissor-like levers 4 and 4' which are freely movable by means ofrollers 5 and 5' over the surfaces of flange ring B. Supporting wire Apasses through flange ring B and is attached to the fulcrum ofscissor-like levers 4 and 4'. As the supporting wire A expands, levers 4and 4 will tend to close. Spring 6, by tending to draw together the endsof levers 4 and 4', continually maintains tension in supporting wire A.Thus it may be seen that this modification also allows supporting wire Ato expand and contract while automatically being under tension. Figure2a illustrates an application of this modification.

Another means for continually keeping supporting wires A in a state oftension, which is particularly suitable when said supporting wiresareplaced in a vertical position, is illustrated in Figures 3 and 3a. Itconsists of a scissor-like device, similar to that of Figure 2,comprising levers 1 and I, rollers 8 and 8' and weights 9 and 9'. Thefree end of supporting wire A is attached to the fulcrum of thescissor-like device and is continually kept in tension while beingallowed to expand and contract due to the action of weights 9 and 9'which tend to force rollers 8 and 8' towards one another and to thusraise th fulcrum.

What I claim is:

1. Apparatus for carrying out catalytic reactions comprisingcatalytically active metal wire gauze arranged transverse to thedirection of flow of the reactants, supports for said catalyticallyactive metal wire gauze andan automatically acting tension device tomaintain said supports in a tightly stretched condition duringoperation, the catalytically active metal wire gauze resting looselyagainst the supports and being subjected to none of the tension impartedto said supports.

2. Apparatus for carrying out catalytic reactions comprisingcatalytically active metal wire gauze arranged transverse to thedirection of flow of the reactants, supports for said catalyticallyactive metal wire gauze and a tension device acting automatically byspring action to maintain said supports in a tightly stretched conditionduring operation, the catalytically active metal wire gauze restingloosely against the supports and being subjected to none of the tensionimparted to saidsupports.

3. Apparatus for carrying out catalytic reactions comprisingcatalytically active metal wire gauze arranged transverse to thedirection of flow of the reactants, supports for said catalyticallyactive metal wire gauze and a tension device acting automatically byloading with weights to maintain said supports in a tightly stretchedcondition during operation, the catalytically active metal wire gauzeresting loosely against the supports and being subjected to none of thetension imparted to said supports.

O'ITO BAADER.

